Post by thread:[PICLIST] [PIC] PIC C Compiler Constants

Hi all, How can I do to make the line: SPBRG=FOSC/BAUD/16-1; assign the correct value to SPBRG in Hi-Tech Pic C Compiler? Actually it truncates the value of FOSC/BAUD/16, and I want the rounded value. I have defined FOSC and BAUD this way: #define MHZ *1000000 #define FOSC 4MHZ #define BAUDIOS 28800 Thanks, Alvaro -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body

Alvaro Deibe Diaz <PICLISTKILLspammitvma.mit.edu> wrote: > How can I do to make the line: > > SPBRG=FOSC/BAUD/16-1; > > assign the correct value to SPBRG in Hi-Tech Pic C Compiler? > > Actually it truncates the value of FOSC/BAUD/16, and I want the > rounded value. Alvaro: SPBRG == (FOSC/BAUD/8 + 1)/2 - 1; -Andy === Andrew Warren --- .....aiwKILLspam.....cypress.com === IPD Systems Engineering, CYSD === Cypress Semiconductor Corporation === === Opinions expressed above do not === necessarily represent those of === Cypress Semiconductor Corporation -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email EraseMElistservspam_OUTTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

Hi Alvaro, The following works well for me, hope it works for you too (I'm sure I originally got this from a Hi-Tech sample file but can't find it again now). I put all the #defines in a header file serial.h and the init routine and other serial stuff in serial.c. When I need to change baud rate or crystal frequency for a project then I just need to edit the values in the header file. #define BAUD 2400 // Serial comms paramters for init #define FOSC 1843200L #define NINE_BITS 0 // Use 9bit comms? FALSE=8bit #define HIGH_SPEED 0 #define DIVIDER ((int)(FOSC/(64UL * BAUD) -1)) // Divider for low speed //#define DIVIDER ((int)(FOSC/(16UL * BAUD) -1)) // Divider for high speed void InitComms(void){ BRGH = HIGH_SPEED; SPBRG = DIVIDER; SYNC = 0; SPEN = 1; CREN = 1; SREN = 0; ADDEN = 0; TXIE = 0; // Disable Tx interrupt RCIE = 1; // Enable Rx interrupt TX9 = NINE_BITS; RX9 = NINE_BITS; TXEN = 1; TRISC7 = 1; TRISC6 = 1; } Brent Brown Electronic Design Solutions 16 English Street Hamilton, New Zealand Ph/fax: +64 7 849 0069 Mobile/text: 025 334 069 eMail: brent.brownspam_OUTclear.net.nz -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email @spam@listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body